diff --git a/make/py-topdir.mk b/make/py-topdir.mk
index 4a298642..471ee8b4 100644
--- a/make/py-topdir.mk
+++ b/make/py-topdir.mk
@@ -1,7 +1,9 @@
 TD_COPY_FILES               += pyproject.toml
 
 PY_CHECK_EXCLUDE            ?=
-PY_SRC_ROOT                 += $(wildcard $(TOPDIR)/src $(TOPDIR)/tools)
+ifndef PY_CHECK_ROOTS
+  PY_CHECK_ROOTS            += $(wildcard $(TOPDIR)/src $(TOPDIR)/tools)
+endif
 
 ifndef PY_CHECK_RUFF
   PY_CHECK_RUFF             := $(shell which ruff 2>/dev/null)
@@ -25,27 +27,27 @@ check-format: py-check-format
 py-check: py-check-syntax py-check-format
 py-check-syntax:
 ifneq ($(PY_CHECK_RUFF),)
-	$(PY_CHECK_RUFF) check $(addprefix --exclude ,$(PY_CHECK_EXCLUDE)) $(PY_SRC_ROOT)
+	$(PY_CHECK_RUFF) check $(addprefix --exclude ,$(PY_CHECK_EXCLUDE)) $(PY_CHECK_ROOTS)
 endif
-	mypy $(addprefix --exclude ,$(PY_CHECK_EXCLUDE)) $(PY_SRC_ROOT)
+	mypy $(addprefix --exclude ,$(PY_CHECK_EXCLUDE)) $(PY_CHECK_ROOTS)
 ifneq ($(PY_CHECK_PYRIGHT),)
-	pyright
+	pyright $(PY_CHECK_ROOTS)
 endif
 
 py-check-format:
 ifneq ($(PY_CHECK_YAPF),)
-	$(PY_CHECK_YAPF) --diff --recursive .
+	$(PY_CHECK_YAPF) --diff --recursive $(PY_CHECK_ROOTS)
 endif
 
 py-format:
 	find . -type f -name '*.py' -print0 | \
 		xargs -0 sed -i -E '1{/^# -\*- coding: utf-8 -\*-$$/{:a;N;/\n[[:space:]]*$$/ba;s/^# -\*- coding: utf-8 -\*-\n([[:space:]]*\n)*/ /;s/^ //}}'
 ifneq ($(PY_CHECK_YAPF),)
-	$(PY_CHECK_YAPF) --in-place --recursive .
+	$(PY_CHECK_YAPF) --in-place --recursive $(PY_CHECK_ROOTS)
 endif
 
 py-format-assignments:
-	find . \
+	find $(PY_CHECK_ROOTS) \
 	  -path './.git' -prune -o \
 	  -type f -name '*.py' \
 	  -execdir /usr/bin/sed -i 's/^\(\s\+[a-zA-Z0-9_]\+\)=\([^,[:space:]]\+\)\([,(]\)*\s*$$/\1 = \2\3/g' {} '+'
@@ -53,12 +55,12 @@ py-format-assignments:
 
 py-check-annotation-imports:
 ifneq ($(PY_CHECK_RUFF),)
-	$(PY_CHECK_RUFF) check --select TC,FA --diff --unsafe-fixes .
+	$(PY_CHECK_RUFF) check --select TC,FA --diff --unsafe-fixes $(PY_CHECK_ROOTS)
 endif
 
 py-format-annotation-imports:
 ifneq ($(PY_CHECK_RUFF),)
-	$(PY_CHECK_RUFF) check --select TC,FA --fix --unsafe-fixes .
+	$(PY_CHECK_RUFF) check --select TC,FA --fix --unsafe-fixes $(PY_CHECK_ROOTS)
 endif
 
 clean.topdir: clean.py-check